Nonsinusoidal motion effect on a self-propelled heaving foil

Abstract

In order to explore the mechanism of bionic propulsion and bionic robots, to make up for the limitations of traditional propulsion with a uniform incoming flow, numerical methods are used to couple fluid dynamics and flapping foil motions, and a flapping-fluid coupling self-propulsion calculation model is established in this paper. K is used as the waveform adjustment parameter to change the waveform from triangle wave to sine wave and square wave. The self-propulsion performances of non-sinusoidal heave motion under two frequency-heaving amplitude combinations are numerically simulated to study the influence of different motion waveforms on self-propulsion velocity, efficiency and flow field structure in still water. The results show that the non-sinusoidal waveform has a great influence on the self-propulsion. With the increase of K, the closer to the square wave, the more violent the speed oscillation, the faster the starting acceleration, the greater the forward displacement and the average speed, as K decreases, self-propulsion efficiency and energy utilization continue to increase. The results of this study have certain guiding significance for the design of bionic underwater vehicles.